TGFB2 and glaucoma: One of the seminal works identified in the literature used enzyme-linked immunosorbent assay (ELISA) to determine the presence of altered levels of transforming growth factor-beta 2 (TGF-β2) in samples of aqueous humor from 15 patients with POAG and 10 age-matched control subjects undergoing cataract surgery, constituting one of the first attempts to discover candidate biomarkers of glaucoma [40].